I know I’m very late on this matter, but I recently found out about custom challenges and their making. I’ve already made two and completed them but my friend and I were fooling around the options but we could not manage to get a LASO challenge working. The options were very stubborn and even though we got the campaign mission and all skulls on, we could not take off the number of kills, medals, etc. Is there a way to do that?
It looks like you can’t take off the the kills, sorry.